Some of the work leading to the present invention was done within the field of thruster technology for space applications. Here the decompositions of the propellant, such as hydrazine or hydrogen peroxide, is activated by passing the propellant over a hot catalytic bed containing PGM elements, such as platinum, palladium, or iridium. The current state-of-the-art is to use a powdered ceramic material containing an active catalyst and to press the loose powder between metallic top and bottom gauzes in order to make a porous powder pack. One of the known problems with loose powder in between gauzes is that the powder can sometimes remove itself and fall out of the thruster into the exhaust system. This leads to an accelerated degradation of the pack, a reduction in its performance, as well as fine powdered material being emitted as space debris.
An alternative is open-cell ceramic foams which can be used in applications such as catalytic converters for exhaust treatment and other high-temperature applications taking advantage of the high-temperature and chemical resistance as well as the high strength-to-weight ratios achievable by the ceramic foams. It is known from U.S. Pat. No. 4,808,558 to manufacture ceramic foam from an open-cell, reticulated precursor metal. Hereby ceramic articles of randomly interconnected cells or channels have been made. The inner structure of such an article is closely related to the available types of metal foams. Furthermore such random structure may result in a turbulent fluid flow which can be advantageous for some applications. However, for other applications other types of flow would be desired.
Hence, an improved method of manufacturing a ceramic article would be advantageous, and in particular a method with which a high degree of freedom to design parts with controlled internal and external details previously considered too intricate. This fits with the requirement of many applications.